"The possibility of scientific annihilation of personal identity, or even worse, its purposeful control, has sometimes been considered a future threat more awful than atomic holocaust... These objections, however, are debatable."

So wrote Dr Jose Delgado in his 1969 book Physical Control of the Mind: Toward a Psychocivilised Society. Delgado documents the myriad applications of electrical stimulation of the brain, from helping the blind see again to keeping criminals and dissidents under remote control. The Spanish neurologist's hopes rested on a device he called the "stimoceiver". Once inserted into the required part of the brain, the remotely operated stimoceiver could stimulate it electrically. In a dramatic demonstration in the early 1960s, Delgado entered a bullring and, at the press of a button, stopped a charging bull dead in its tracks. Delgado saw great potential in his creation, but he did note one possible problem: "The existence of wires leading from the brain to the stimoceiver outside of the scalp... could be a hindrance to hair grooming."

Modern day proponents of the mind control conspiracy use Delgado's stimoceivers to support their suspicions; but how far has the technology advanced?

Last year US scientists revealed a team of rats that could be remote-controlled from a laptop. Electrodes in the rodents' brains activate their pleasure centres while steering them left or right. A tiny backpack acts as a receiver. The robo-rats were presented as the very latest in biotechnology, but in his memoirs the late neurologist John Lilly, who began his career working on the electrical stimulation of animal brains, recalled seeing a military film of a donkey being remotely steered up a hillside in the 1950s.

Whether we have the technology to control another human mind, brain implants are now being used to help the victims of paralysis. Dr Philip Kennedy of Neural Signals has developed an implanted device that allows JR, a paralysed 53-year-old volunteer, to move a mouse cursor around a computer screen using thought alone. There are no wires - a small antenna, connected to the implant, pokes out of the top of JR's skull.

We may be approaching Delgado's psychocivilised society, but that hair is going to be a problem for some time yet